Field of the Invention
The present invention relates to a device for internal cooling and pressurization, and more particularly, to a device for internal cooling and pressurization of a rotary engine, which allows a rotary engine to realize dual functions of internal cooling and pressurization, in achieving optimum performance.
Description of the Related Art
In general, due to its high horse power/volume ratio, Rotary Engine has wide applications in the Industries, since it is capable of generating greater horse power at less volume. Yet, it may also produce greater heat at less volume. Therefore, the heat dissipation problem is crucial in its performance. In case the heat generated can not be dissipated properly, that could adversely affect the performance and efficiency of the rotary engine. In order to sufficiently cool a rotary engine during operation, both the external and internal cooling are required, and that can be achieved through using air cooling, oil cooling, or water cooling. Yet, presently, in this respect, the existing technologies all have their deficiencies and shortcomings, as explained as follows.
The performance of the rotary engine is basically determined by its geometry including the air intake/exhaust time sequence arrangement (port site), the ignition timing, the cylinder volume, the air fuel ratio, and the like. Because the rotary engine contains three chambers (the cylinder) and has the property of the small size, the heat dissipation is always an urgent problem in the development. In the past years, the development of the heat dissipation mainly adopts the air cooling on the external. However, as the power required increased, the heat dissipation requirement is also rising, and the existing problems and shortages of the air cooling apparently appear. Thereby, manners of the water cooling and the oil cooling are developed for solving these problems and shortages. Nevertheless, most devices with functions of water cooling or oil cooling still focus on the external cooling. As opposed to the reciprocation engine, the internal of rotary engine also needs a better heat dissipation to reduce the abrasion on the crank shaft by high-temperature deformation and worsen the efficiency. Water or oil cooling, effective on the external cooling, is rarely adopted in the internal of a rotary engine for its sophisticated air passage pulsating flow, and thus air cooling is still widely used.
The rotor core cooling development mainly adopts ram pressure by the carrier velocity with an intake duct to guide the air flow into the core path for the heat dissipation. The mentioned manner is adopted in the rotor core cooling in dealing with high heat load at high rotational speed when outputting higher power. Therefore, it is the main purpose to increase the amount of cooling air at high RPM. As aforementioned, the complicated pulsating (discontinuous) air flow and high passage blockage make the cooling flow less. Though, at high rotational speed, increased ram pressure is required to raise the cooling flow, at low RPM, the cooling flow is little. The cooling lubricant oil in bearings works on heat dissipation of rotor crank shaft, and that is insufficient. As heat dissipation is concerned, redesign oil/lubrication system is time and cost consuming with its complexity.
With regard to the existing technology for air cooling of engines, U.S. Pat. No. 8,141,360 discloses a “Hybrid Gas Turbine and Internal Combustion Engine”. In which, ambient air is first drawn by suction through the inlet filter 10, and then compressed in the gas turbine compressor 12. The compressor exhaust flow then splits into several flows. One flow through the inlet valve 42 is provided as the supercharged inlet flow to the internal combustion engine 30, which operates continuously throughout the mission (line 49 of column 4, FIG. 1), then the engine exhaust is input to a combustor 16 for combustion. The major purpose is to keep the turbine engine in low power output state, to keep it run continuously (line 5 of column 5, FIG. 1). Another exhaust flow flows from the compressor 12 to the valve 43, then it flows through an engine cooling circuit 31 into the internal combustion engine 30, with the purpose of keeping the turbine engine in low power output state, and keeping it to run continuously. The subject patent is not related to providing internal cooling for the rotary engine to raise its cooling efficiency. The internal combustion engine does not have the design and function of rotary engine internal cooling.
In addition, U.S. Pat. No. 2,384,381 discloses an “Internal Combustion Engine”, in which supercharged air is delivered to either the intake manifold of the engine or to a cooling jacket surrounding the cylinder (lines 4-8, column 1, FIG. 1). While within each cylinder 10 is provided with a reciprocable piston 11 (lines 47-48, column 2, FIG. 1). As such, the subject patent relates to external cooling for a cylinder of a piston engine. The subject patent is not related to providing internal cooling for the rotary engine to raise its cooling efficiency. The piston engine does not have the design and function of rotary engine internal cooling.
Further, refer to FIGS. 5(a) and 5(b) for a schematic diagrams of a conventional internal cooling system for a rotary engine of the Prior Art. As shown in FIGS. 5 (a) and 5(b), the rotary engine 500 includes: a front frame 51, a mid-frame 52, and a rear frame 53, a rotor 54, a crank shaft 55, a core cooling intake pipe 56, a core cooling exhaust pipe 57, an engine air intake pipe 58, an engine air exhaust pipe 59, and a plurality of cooling fins 511 and 513 provided on the circumference of the front frame 51 and the rear frame 53. In this structure, cooling fins 511 and 531 are used to achieve external cooling. For internal cooling, the rotor 54 is disposed in the mid-frame 52, and having a plurality of core cooling channels (not shown) passing through in connection with the openings in both the front and rear frames 51 and 52 for receiving clean air and exiting exhaust air respectively, in achieving internal cooling of the rotary engine.
In the structure mentioned above, for internal cooling involving rotary engine on the ground, a super charger has to be connected to one end of the core cooling intake pipe 56, through which compressed air is supplied to the rotary engine to achieve cooling. In this respect, no super charger is required to be connected to the engine air intake pipe 58, since the rotation of the rotary engine could generate a suction force strong enough to take in sufficient air, for the combustion of the rotary engine.
Therefore, the drawback of this type of rotary engine is that, when the rotary engine is used to operate in a high flying airplane, since the air is rather cool in such a high altitude, while the ram air flow of the airplane is strong enough to take in sufficient air into the core cooling intake pipe for internal cooling, as such, the super charger connected thereto is laying idle and useless, and that constitutes quite a waste. Further, when the rotary engine is in a high flying airplane, the atmospheric pressure is much reduced due to high altitude, such that the pressure of air taken into the engine air intake pipe is rather insufficient, to affect the combustion and the performance of the rotary engine.
As such, in this way, the rotary engine can not achieve efficient cooling and performance.
Therefore, presently, the design and performance of the rotary engine internal cooling and pressurization is not quite satisfactory, and it leaves much room for improvement.